Research On The Dynamic Modulation Of Slow Light In A Two-dimensional Photonic Crystal Waveguide Based On The Electro-optic Effect

In recent years,human society has entered an era of rapid development of information technology,and there are different degrees of dependence on information technology in all fields of society.The rapid growth of information rates and communication capacity makes great challange to the existing communication networks.In today's communication networks,many nodes are required to convert optical signals-electrical signals-optical signals.Therefore,the limitations of bandwidth and power consumption of electronic devices have become an urgent problem in the implementation of high-speed and largecapacity communication networks,that is,the phenomenon of "electronic bottleneck".In order to break through this limitation,people turn their attention to all-optical networks with high speed and large capacity.Optical buffers are the key commponets in the ruting and switching of all-optical networks.The optical buffer device is mainly realized by slow light technology.Among many media slow light technologies,photonic crystal slow light has become a research hotspot due to its low group speed,large bandwidth,small size,room temperature operation,flexible structure design and easy integration.However,in practical applications,the photonic crystal must be able to dynamically adjust the slow light characteristics by changes in external conditions.Optical delay line,optical buffer,optical filter and optical switch can be dynamically adjusted by dynamic control of photonic crystal.Therefore,it is of great practical significance to study the dynamic modulation of slow light transmission.In this paper,the propagation and cache characteristics of slow light in photonic crystal waveguides are studied,and the dynamic modulation of slow light characteristics is discussed in detail.The main contents are as follows:1.The basic concepts,characteristics,applications and theoretical research methods of photonic crystals are briefly introduced.The basic concepts of slow light and the mechanism of slow light generation in photonic crystals are summarized.The principle of several physical effects of dynamic control of photonic crystals is analyzed.2.A line defect photonic crystal waveguide structure composed of a circular air hole arranged in a triangular lattice is designed.In terms of structural design,unlike previous literature on the optimization of single factor adjustment in structure and material,this paper combines structural adjustment and material filling to optimize the transmission characteristics of photonic crystal slow light,and obtains optimal photonic crystal waveguide structure with continuous adjustable group refractive index.Filling organic polymers with electro-optic properties into the second row air holes on both sides of the optimal waveguide,the variation of slow light transmission characteristics with external modulation voltage is studied,and the condition of continuous dynamic control of slow light transmission speed is obtained.3.A coupled cavity photonic crystal waveguide structure in which a silicon dielectric rod is placed in a polymer substrate in a triangular lattice structure is designed to obtain a slow light transmission in which the group refractive index is increased by an order of magnitude and the normalized delay bandwidth product is increased by 3 times.The slow light transmission characteristics and the buffer performance of the waveguide structure are optimized by adjusting the size of the dielectric rods around the coupling cavity.The optimal coupling cavity photonic crystal waveguide structure has both large NDBP and large storage capacity,that is,the transmission characteristics and cache characteristics of slow light are optimimal at the same time.Then,through external voltage control,the dynamic variation of transmission characteristics and buffer performance of the optimal coupled cavity waveguide structure are studied.4.The research is summarized and the future work is prospected.The main innovations of this paper are as follows:1.In the optimization of the designed photonic crystal line defect waveguide structure,the slow light characteristics of the waveguide structure are optimized by adjusting the structure and material.Finally,a waveguide structure that maintains optimum slow light characteristics regardless of the material filled is obtained.Under the modulation of the applied voltage,a group refractive index with a continuously variable change can be obtained.2.In the research of the photonic crystal coupled cavity waveguide structure,by adjusting the size of the background dielectric rods and the surrounding microcavity dielectric rods,an optimal coupled cavity photonic crystal waveguide is abotained.In which the slow light transmission characteristics and the buffer performances of the waveguide structure are simultaneously optimized.And under the modulation of variable applied voltages,its transmission characteristics and cache characteristics always maintain a fairly ideal state.